Pollen Trapping: Observations on Colony Dynamics and Honey Production by Kevin Dolan

Introduction

This week we have the last article in the present series on honey bee nutrition and pollen. Kevin Dolan from Canada presents his interesting and timely article on trapping pollen in this guest blog. Thank you very much, Kevin, for supporting the website and contributing your recent work. I’ve been reading some of your classmate’s work in the American Bee Journal and am impressed by the amount of work that has gone into each study and report. High quality stuff.

Master Beekeeper Program

The following article summarizes a research project I put together for the Master Beekeepers program at the University of Montana. The study examined the impact of pollen trapping on honey bee colony functions, specifically focusing on foraging behavior and honey production.

I wanted to try to understand the differences between what the science said versus what commercial producers experienced.

The Role of Pollen and the Mechanics of Trapping

Pollen is the primary source of protein, lipids, and vitamins for honey bees, making it essential for brood rearing and colony sustainability. Shortages can lead to compromised health and reduced population growth. Pollen trapping involves installing a pollen trap at the hive entrance or bottom board that forces returning foragers through a screen. This screen physically removes a portion of the pollen loads from the bees’ hind legs (corbicula) before they enter the hive.

The traps can be used for varying durations—from a few weeks to an entire season—and can be “turned off” to allow bees free passage during periods of high colony pollen needs or poor foraging conditions.

Impact on Foraging Behavior and Honey Yield

A concern regarding pollen trapping is how it alters the colony’s foraging force. Peer-reviewed studies consistently show that colonies respond to the loss of incoming pollen by increasing their pollen-gathering efforts. Research by Dalal et al. (2024) and Duff & Furgala (1986) suggests that the colony can compensate for lack of pollen for brood rearing, by redirecting nectar foragers to collect pollen instead.

This shift in labor has a measurable effect on honey production. Four out of the five major papers reviewed, indicated a decrease in honey yield ranging from 16% to 32.19%. For example, Nelson (1987) found a 20% average reduction in honey over a three-year study, while Hoover & Ovinge (2018) noted a 32% decrease during a shorter three-week trapping period.

Interestingly, interviews with commercial beekeepers Carolyn Eussance, Racheal Herrington, and Albert Devries showed a contrast to these findings. While they acknowledged a potential 10% drop in honey, they reported no significant negative impact on their operations. This difference likely stems from the specific geographical areas of their apiaries—which feature high-density nectar and pollen flows—and the use of modified trap designs.

Trap Design and Efficiency

The efficiency of a pollen trap refers to the percentage of pollen it removes from foragers. Levin & Loper (1984) noted that efficiency can vary widely, from 30% to 66%. The Ontario Agricultural College (OAC) trap, a common design used by commercial operators, is often cited as having a 40% to 50% efficiency rating, though this figure remains largely unverified.

Efficiency is influenced by several variables:

• Hole size and shape: The diameter of the screen holes determines how easily a bee passes through and whether the pollen pellets are stripped off.
• Bee size and behavior: Bees may physically adapt by squeezing their legs closer to their bodies to bypass the screen, resulting in smaller pollen loads
• Maintenance: If the trap is not cleaned regularly, it can become a physical barrier that restricts bee traffic, that could lead to congestion and reduced foraging.

 Management Options for Small-Scale Operations

For beekeepers managing a smaller number of hives, the research suggests that “strategic” rather than “continuous” trapping is the most “sustainable”, way. Continuous or full-season trapping (April through October) carries the highest risk of reducing honey yield and potentially weakening the colony before winter.

1. Selection of Colonies

Trapping should only be performed on strong, queenright colonies. The commercial standard is a minimum of three to five frames of brood in early May. Weaker colonies should be allowed to build their populations without the added stress of a trap, as they lack the forager force necessary to compensate for the lost protein.

2. Timing and Duration

The most effective strategy is to trap during a 3- to 4-week window during a major early-season flow. This timing coincides with high pollen availability and allows the colony to recover its honey and pollen stores later in the summer. Hoover & Ovinge (2018) demonstrated that even with a reduction in honey, the revenue generated from pollen during a short window can significantly increase the total economic return of the hive.

3. Monitoring for Queen Issues

The pollen drawer serves as a secondary indicator of colony health. A sudden absence of pollen in the drawer during a flow often signals a queen-related issue, such as swarming or a queenless state. Because there is no open brood to feed, the bees’ stimulus to collect pollen drops immediately.

Economic and Overwintering Considerations

The decision to trap involves a trade-off. While pollen can be more valuable per pound than honey, beekeepers must ensure they aren’t compromising the colony’s survival. Nelson (1987) reported increased overwintering losses in colonies that were trapped continuously throughout the season.

Economic and Overwintering Considerations

In the late summer and fall, bees must build up “fat bodies” to survive the winter. This requires an abundance of pollen. Consequently, trapping should be avoided in the late season to ensure that the “winter bees” have the protein required for longevity and aid in early spring brood buildup. 

Summary of Best Practices

Based on what I found in the study, the following practices are some recommendations for sustainable pollen collection:

• Limit duration: Trap for short periods (3–4 weeks) during peak spring flows.
• Prioritize strength: Only install traps on hives with at least 3–5 frames of brood.
• Assess efficiency: Use traps that allow a significant portion of pollen (approximately 50%) to bypass the screen.
• Maintain equipment: Inspect and clean traps weekly to prevent entrance congestion.
• Cease late-season trapping: Remove traps by early August (in North America), to allow for winter preparation.

Conclusion

Pollen trapping can be a way to yield some more income from your hives, but it requires active management and an understanding of colony nutrition. The literature indicates a reduction in honey yield, but the economic gain from pollen can make it an option, if it fits with your own beekeeping goals. By focusing on colony strength and limiting the duration of the trap, small-scale beekeepers can harvest pollen, in a sustainable fashion.

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References and Further Reading

• Hoover, S. E., & Ovinge, L. P. (2018). Pollen collection, honey production, and pollination services. Journal of Economic Entomology.
• Duff, S. R., & Furgala, B. (1986). Pollen trapping honey bee colonies in Minnesota (Parts I & II). American Bee Journal.

Brodschneider, R., & Crailsheim, K. (2010). Nutrition and health in honey bees. Apidologi